1. Field of the Invention
Aspects of the present invention relate to a method and apparatus for providing updated information using power control in a portable terminal device.
2. Description of the Related Art
WiBro is the abbreviation for Wireless Broadband Internet. WiBro is a super high speed Internet service for connecting to the Internet using a portable terminal whenever and wherever at a high transmission speed of about 1 Mbps. WiBro can be used while the portable terminal is at rest or in motion. With WiBro, the concept of an indoor wired super high speed Internet service is extended to a wireless service that can be used during movement.
FIG. 1 illustrates a structure of a communication system in a WiBro network. The WiBro network includes a plurality of cells 100 and 150, base stations 110 and 140 for managing the cells 100 and 150, and a number of mobile subscriber stations (MSSs) 111, 113, 130, 151, and 153. Signal transmission/reception between the base stations 110 and 140 and the MSSs 111, 113, 130, 151, and 153 is performed using an orthogonal frequency division multiplexing (OFDM) method and/or an orthogonal frequency division multiple access (OFDMA) method. The MSS 130 is placed in a border area. Mobility for the MSSs 111, 113, 130, 151, and 153 can be supported only when a handover for the MSS 130 is supported.
Power consumption of the MSS is an important factor over the entire system. In order to minimize the power consumption of the MSS, a sleep mode, an awake mode, and an idle mode between the MSS and the base station is proposed.
FIG. 2 illustrates operation modes supported by a WiBro communication network. The WiBro communication network supports several operating modes: a null mode 210, a standby mode 220, an awake mode 230, a sleep mode 240, and an idle mode 250. The null mode 210 and the standby mode 220 are operating modes used when the portable terminal device is not connected to the WiBro network. The awake mode 230, the sleep mode 240, and the idle mode 250 are operating modes used when the portable terminal device is in the WiBro network.
The null mode 210 is a state where the portable terminal device is turned off. The standby mode 220 is a mode for attempting to connect to the WiBro network by supplying power to the portable terminal device. The awake mode 230 is a mode in which a user can connect to the Internet and perform retrieval, upload, and download. The sleep mode is a minimum power state where only an Internet protocol (IP) is maintained by transmitting minimum information on the portable terminal device to a system for periodically managing the WiBro network. The idle mode 250 is a state where the power to the portable terminal device is turned off but the IP is not registered.
As described above, in the related art, data cannot be sent through the network while the portable terminal device is in the sleep mode. In order to communicate data, the sleep mode has to be changed to the awake mode so as to turn on the portable terminal device. As a result, power consumption of the portable terminal device cannot be effectively controlled.